Increasing the range by Pedal Assist?

[ProDigit]

You don't really need pedalling all the time.
It costs most electricity to start from standstill to upto speed (the acceleration process).
Remaining accelerated on a straight (horizontal) plane, takes very little from an engine.

IMHO, one could create a nice bike having only a 200W engine, just enough to maintain speed. Accelerating from a red light, or traveling uphill (a few degrees) should not make a person very tired, as the acceleration process only requires a few seconds of physical labor, and driving uphill can be 50% compensated by the electrical engine.

I love this video of this guy, his bike goes pretty fast too, with an engine powerful enough to accelerate slowly to 50MPH (=lethal speed).
He also uses his pedals to do the initial startup, but soon the bike goes too fast to catch up pedaling with the engine.

[rui_fujino]

You don't really need pedalling all the time.
It costs most electricity to start from standstill to upto speed (the acceleration process).
Remaining accelerated on a straight (horizontal) plane, takes very little from an engine.

IMHO, one could create a nice bike having only a 200W engine, just enough to maintain speed. Accelerating from a red light, or traveling uphill (a few degrees) should not make a person very tired, as the acceleration process only requires a few seconds of physical labor, and driving uphill can be 50% compensated by the electrical engine.

I love this video of this guy, his bike goes pretty fast too, with an engine powerful enough to accelerate slowly to 50MPH (=lethal speed).
He also uses his pedals to do the initial startup, but soon the bike goes too fast to catch up pedaling with the engine.

If we dont need to pedal at all the time then we wouldnt be talking about increasing range since it becomes impossible..lol I do agree that you can help the range by starting up from dead stop. when we go over 30mph it uses more energy to keep us going at high speed therefore every pedalling will help us gain more distance. I dont think using 200w MOTOR would help the person stay at high speed cos if this is true then the motor is capable of reaching high speed on its own without pedalling.
Im sorry but that's stealth bomber ...so he is not exactly using small hub either...and I believe he's got +72v setup anyway so I cant imagine him pedalling it more than most of us who pedals to increase range

if you love that video you should watch more by GCinDC. he has more exciting vids
PS: engine = motor...

[SamTexas]

I love this video of this guy, his bike goes pretty fast too, with an engine powerful enough to accelerate slowly to 50MPH (=lethal speed).
He also uses his pedals to do the initial startup, but soon the bike goes too fast to catch up pedaling with the engine.

Are we watching the same video? Where exactly did he do any pedalling? None that I saw. He did move his legs every now and then, but I'm sure he did that out of boredom or wanting to get some blood circulated.

[ProDigit]

I love this video of this guy, his bike goes pretty fast too, with an engine powerful enough to accelerate slowly to 50MPH (=lethal speed).
He also uses his pedals to do the initial startup, but soon the bike goes too fast to catch up pedaling with the engine.

Are we watching the same video? Where exactly did he do any pedalling? None that I saw. He did move his legs every now and then, but I'm sure he did that out of boredom or wanting to get some blood circulated.

That'd be beside the point of the discussion, but yes, he pedals to accelerate from every stop light. Somewhere he meets up with gas powered scooters, and pedals them right by, aided by his 'motor'.

[SamTexas]

That'd be beside the point of the discussion, but yes, he pedals to accelerate from every stop light. Somewhere he meets up with gas powered scooters, and pedals them right by, aided by his 'motor'.

Yeah right! He was moving at speed of at least 30mph, and he was pedalling right by at a cadence less than 30. And it's not besides the context of this thread. Fake pedalling is just that, fake. He could have pedalled BACKWARD to achieve the same thing.

[ProDigit]

I don't know if you reply just because you feel the urge to be right or not,
but it shows you haven't seen the whole video, before posting your post.
In the last third of the video the rider stands still at a number of stoplights, and pedals to gain momentum.

I don't even know why I need to explain myself if you just criticize what I wrote without verifying; if you'd only seen the whole video you'd save yourself (and others) some agitation time

[rui_fujino]

I don't know if you reply just because you feel the urge to be right or not,
but it shows you haven't seen the whole video, before posting your post.
In the last third of the video the rider stands still at a number of stoplights, and pedals to gain momentum.

I don't even know why I need to explain myself if you just criticize what I wrote without verifying; if you'd only seen the whole video you'd save yourself (and others) some agitation time

ok ive watched it twice and yes he does use his pedal twice in whole video from dead stop. However, from my knowledge of his bike, its too heavy to pedal that lightly to get that much of speed easily. so i think he was using motor +pedal to start off (at best if not faking pedalling )
I believe this video is quite irrelevant to to this thread since your first post suggested we dont need to pedal once we get our speed going is not true.

[SamTexas]

However, from my knowledge of his bike, its too heavy to pedal that lightly to get that much of speed easily. so i think he was using motor +pedal to start off (at best if not faking pedalling )

That's what I was trying to tell him. But I guess it's too much for a guy riding a fake ebike with pretend-only pedals to understand. This guy came to this thread not to discuss pedal assist. He came with the attempt to convince people he bought a real ebike (only in his deluded mind of course.)

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I believe this video is quite irrelevant to to this thread since your first post suggested we dont need to pedal once we get our speed going is not true.

Agreed. The video is just show off of a ridiculously expensive ebike and has nothing to do with pedal assist.

I don't know if you reply just because you feel the urge to be right or not,
but it shows you haven't seen the whole video, before posting your post.

Wrong. It shows that you lack the most basic understanding of pedal assist.

[ProDigit]

So it seems like everywhere in the world there are a bunch of teenagers on forums, who can't seem to agree to be wrong.

That's what I was trying to tell him. But I guess it's too much for a guy riding a fake ebike with pretend-only pedals to understand. This guy came to this thread not to discuss pedal assist. He came with the attempt to convince people he bought a real ebike (only in his deluded mind of course.)

No need to start lying and getting rude?
I came to rob your mother, clear?

Agreed. The video is just show off of a ridiculously expensive ebike and has nothing to do with pedal assist.

Shows pedal, motor assisted,doesn't it?

Wrong. It shows that you lack the most basic understanding of pedal assist.

Ow? In my impression, any motor that is assisting a bike with pedals is pedal assisted.
Perhaps your puny brain is not large enough to understand other people can understand this without having to spend 5 weeks getting your GED before you understand.

[rui_fujino]

okay, forget the last few posts. Now think this way, is a guy on the video increasing the range by pedal assist? Answer is yes but only a little as 5% or less.
the thread is about using pedal at high speed or average speed(+40mph = high speed, 20~30mph = average speed). Now it is common sense to pedal at the beginning to save the power for acceleration.
ProDigit, I guess my point is,

Remaining accelerated on a straight (horizontal) plane, takes very little from an engine.

is wrong. for ES members, we have high speed ebikes thus we use a lot of power to keep us above 30mph.

Rui

[Hillhater]

30mph requires 1000W approx continuous.
40+ mph requires 2+ kW continuous.
Average human can only output 100W continuous.
so at best you can expect a 10% range improvement at 30 mph ( 5% @ 40+ mph ) ....IF you PEDAL HARD CONTINUOUSLY.

But note that at 20 mph , which need only 200W continuous, you could extend your range by 100% !

[ProDigit]

I don't know,
Just a suggestion, but,
It could be that the wrong system is applied for electric bikes.
These brushless engines have a high torq at low RPMs but at higher RPMs become less powerful. also the controller plays a big role in all of this.
I had done electro mechanics in school, it was not in English, but there exists some kind of engine like a brushless engine, with the axis just being a cage, no magnets, no coils, no burshes.

My teacher explained it was a 'series engine' literally translated from my mother tongue.
The difference is that current technology is a parallel engine, which means the higher the voltage the more powerful the engine, but the RPM's are pretty much limited to the controller or phase frequency on an AC network.
In a series engine, the torq is lower, but constant. Even with a low voltage, on a zero ballast, the engine will spin out of control.
These types of engines just provide a constant, low Torq, force, regardless of RPM. If the torq is big enough to get a driver riding, they could accelerate indefinitely if they did not have the wind resistance. These types of engines might be better suited for this job, perhaps, as they're not into precision, but acceleration.

Technically if you find such an engine that can drive you 30mph (when wind resistance nullifies the force the motor is pushing the bike), when wind direction changes, speed can change too. These type of engines are also lousy performers on a hill, but could reach ridiculous speeds downhill without breaking a sweat or even overheating!

@Hillhater: It all depends, the controller limits some engines more than an engine itself limits the bike. It might be possible to go faster with a 500W engine.
Since I don't have the name of the engine I described above, best thing you can do is test a 500W brush motor, apply 48V onto it, and accelerate until the bike accelerates no more. Then you know how fast on average a 500W engine can accelerate.
When the engine has enough torq, try getting a 500W engine with a lower voltage rating, like eg,one that needs 36V to operate if that exists. Plug it on 48V, and see how fast you can go!

[Hillhater]

.... try getting a 500W engine with a lower voltage rating, like eg,one that needs 36V to operate if that exists. Plug it on 48V, and see how fast you can go!

With the DC motors we are considering here, once you increase the voltage from 36 to 48 volts, you directly increase its power by the same ratio. IE your 500W motor is now a 666 W motor, so naturally it will go faster.

However, the speed /power required relationship i quoted is strictly determined by the physical conditions... wind resistance, rolling resistance etc.
The power needed to cruise at those speeds is well understood and documented.
try this ..http://www.kreuzotter.de/english/espeed.htm

[ProDigit]

Very interesting, however I do think that the controller still plays a big role in your overall speed.

You could for instance try to see if increasing wheel size will make the vehicle go faster.
If it is true what you say, increasing wheel size should not improve speed at all.

I think many manufacturers need to see what the best wheel size is. some people only use their vehicles on flat land, and don't mind lower torq at the gain of higher speeds and more miles per charge. They should offer these vehicles with at least 2 types of tires, one with more torq and smaller tires, the other with bigger tires and more speed and miles per charge

[dogman]

Bottom line, as said above, your maximum sustainded effort unless you are on a pro bike race team, is going to be about 100w.

It's a singificant increase if you are running at 200w, to add your 100w. It is not much increase if you are running 1500w, and add your 100w for 20 feet out of each mile. What percentage of a mile is 20 feet? 1/264th of a mile .0 something%? then take 7.5% of that? now you have assisted your motor .00 something%?

You just aint getting doo doo out of pedaling a stealth bomber from the stop sign. It's nothing % added.

Discuss controllers, motor types, and wheel sizes elsewhere in another thread. They have nothing to do with pedal assist efficiency.

[Alastor]

Dogman is right .There are two cases witch i have some experience in both

My ebike not the scooter like one i got in the other post is one 250 watt with pedal assist and throttle.When i took it was testing it with pedal assist the first time and with the throttle after to see the results range wise.When i was going full throttle and no pedaling at all i had a max range of 40 km tops when i was pedaling all the time and using the pedal sensor only the bicycle had a 60 km+ range with a 36v10ah lipo4 battery pack.After some more testing to double check my results i uninstalled the throttle

To the electric scooter now that is also 250 watt but way to heavy (65 kilos instead of 24 that the electric bicycle weights) when i pedal i add to the motor almost nothing because there is only one fixed gear the softer one for going uphill.After 10 kms you cant follow up pedaling because of the gear setup so its also useless and dangers trying to do so.While i do uphill the motor needs my assistance and when i pedal it gives the little push the motor needs to accelerate.That is saving me tons of energy with little effort because i help the motor when it requires it.In a case of a heavier bike or even one with an 800 watt or bigger motor is a lost cause.Same for the bomber you can pedal but what can you add to the 4500 watt motor really??

Some more sophisticated and very expensive bikes (i don't know if the bomber dose that) use the pedaling power to recharge the battery.

[ProDigit]

... use the pedaling power to recharge the battery.

It's actually much better as a direct drive. Generating electricity is only very little, there's a lot more loss when going from kinetic energy to electric and back, then just staying with kinetic energy.

If you want to pedal along, you'll have to have a large gearwheel in the front, and a tiny one in the back.
It'll not allow you to accelerate fast, but it's probably the only way to keep up with an engine going 25mph+

You could also have a small gearwheel in the front, for acceleration.
Since you want to pedal along, to save energy, I suppose you'll need 2 gears to unburden the motor from accelerating, and help it's burden while driving; to keep a comfortable drive. No fun pedalling like crazy to keep up with the engine, and no fun standing on a pedal waiting for it to go down, knowing you barely have torque to go forward!

24 gear Mountain bikes are the best for this! Though you'll probably only need 2 of the 24 gears.

[rui_fujino]

If you want to pedal along, you'll have to have a large gearwheel in the front, and a tiny one in the back.
It'll not allow you to accelerate fast, but it's probably the only way to keep up with an engine going 25mph+

You could also have a small gearwheel in the front, for acceleration.
Since you want to pedal along, to save energy, I suppose you'll need 2 gears to unburden the motor from accelerating, and help it's burden while driving; to keep a comfortable drive. No fun pedalling like crazy to keep up with the engine, and no fun standing on a pedal waiting for it to go down, knowing you barely have torque to go forward!

24 gear Mountain bikes are the best for this! Though you'll probably only need 2 of the 24 gears.

Personally 52T triple chainset and 11T-28T freewheel can give me 35mph cycling to going up the hill at ease without motor!
Its most of us have now access to 11t freewheel from ebike.ca or ebay so I would recommend it to anyone who has problem with pedalling. However, it is very dangerous to pedal beyond 30mph since it will cause bike to be unbalanced.

[ProDigit]

However, it is very dangerous to pedal beyond 30mph since it will cause bike to be unbalanced.

define what you mean by 'unbalanced'?

[rui_fujino]

However, it is very dangerous to pedal beyond 30mph since it will cause bike to be unbalanced.

define what you mean by 'unbalanced'?

Unbalanced as in you have less control over your bike compared to just throttling

[amberwolf]

However, it is very dangerous to pedal beyond 30mph since it will cause bike to be unbalanced.

define what you mean by 'unbalanced'?

When you pedal, the bike rocks side to side, and the front wheel "wobbles" from the weight shifts (unless you hold your arms so rigidly that you will regret it in an hour or two). The faster you go while doing this, the less stable the bike is, depending on the terrain you're on. Nice smooth sticky asphalt isn't so bad, but worn asphalt with loose bits or non-sticky concrete or dirt or gravel is harder to stay in the maneuver you're in already, while this is happening.

If you're a high-powered pedal cyclist already, and have trained yourself to ride well at those speeds while pedalling hard, then you could probably do it without a problem (other than dealing with the weight of the non-bike stuff). But most people can't pedal that fast, or at least not for long enough to worry about handling the bike at those speeds--they're exhausted and have to stop, pretty quickly.